Mike
If you look in the NEC that area would fall into the class 2 chapters. I have done enough grain,and dusty area to get my fill of these areas. You need a lot of care to keep the dust out of the equipment. Good explosion proof equipment is expensive but where needed will save lives and property.
Unfourtunatly I have seen the result of grain and suger dust explosions, no different for TNT for results. Some of those were fatals to employees.
Take care and be safe.
